I want to execute org-babel code blocks of R code in a particular R session without locking up Emacs. I found the ob-async package, but it doesn't have support for sessions yet. I've found that opening the code block in a source buffer allows me to run code blocks without locking up Emacs. I'm mostly happy with that workflow. I can hit C-' C-b to evaluate R code blocks using ESS, for example.
One annoyance however is that I have to choose the instance to use for execution, if I have multiple R sessions open. This is particularly cumbersome, since I have to do this every time I revisit the code block using C-'. I'd like to have the session automatically associated (using the :session argument in the header). How would I go about doing this?